Add these lines to Config/Routes.php as defined in https://codeigniter4.github.io/CodeIgniter4/incoming/routing.html#setting-routing-rules

$routes->get('/', 'Home::index');
//----------------Add Below codes to Config/Routes.php
$routes->get('/home/about', 'Home::test'); //or
$routes->get('/about', 'Home::test');
$routes->get('/youtube', 'Home::youtube');